“We identified these players because we think they can fill a void on our roster,” general manager and technical director Gavin Wilkinson said. “Each one of them was a standout at the college level. Now they need to prove themselves in order to stay with us.”

The Timbers have assembled roughly two-thirds of the 30-player roster they intend to build.

“We’re pushing 20 [players] with one or two pending approval,” Wilkinson said.

Thompson, one of the top scorers in UC-Irvine history, was named to the Hermann Trophy Watch List in 2010. Lynch was the Missouri Valley Conference’s Defensive Player of the Year in 2010. Reza was a first-team All-Pac-10 selection. Mueller was a second-team All-Pac-10 honoree at Washington.

“It’s what I’ve been working towards, a shot to be able to play with the guys in the professional leagues,” Mueller said in a statement. “It’s unreal right now, and for it to be one of the Northwest clubs is amazing to have the opportunity for my family to watch me. It’s awesome to go to Portland, which is a great soccer city.”

The Timbers began taking shape in October and have signed USSF D-2 players, added players through the expansion draft, made trades and secured forward Kenny Cooper through the allocation process.

“As an expansion team we have to look at all possible avenues, all the different mechanisms for bringing in players,” Wilkinson said. “We’ve cast a wide net to find talent.”

Portland will continue to address specific needs over the coming weeks. The club also announced Tuesday that will begin training on Jan. 24 in Portland. The inaugural preseason includes camps in Ventura, Calif. (Feb. 1-8) and Casa Grande, Ariz. (Feb. 18-26).

The first preseason match is set for Feb. 4, when the Timbers will meet the Ventura County Fusion at Ventura College.

The Timbers open the 2011 MLS season on the road at Colorado on March 19.